Continuous process for the refining of oils



Jan. I, 1929.

E. T. HESSLE CONTINUOUS PROCESS FORYTHE REFINING OF OILS Filed March 31,1926 FWXJ (k at 865.5 A

f/za T). HessZe Patented Jan. 1, 1929.

UNITED STATES assen marmorricr.

ERIC 'rn. nnssnn, or LEMONT, rumors.

CONTINUOUS PROCESS FOR THE REFINING Q1 @1118.

Application filed March e1, 1926. Serial No. eager.

This invention relates to a continuous process for the conversion ofhydrocarbon oils into other hydrocarbons of lower boilmg points. Moreparticularly it relates a continuous catalytic process for refiningoils, such as crude petroleum oils, its distillates and residues, taroil, brown coal tar oil, shale oil and similar products.

In so far as it relates to the same subject matter, this application isa continuation in part of my application, Serial No. 678,924, filedDecember 6th, 1923, for a continuous process for .the refining ofmineral oils, now Patent No. 1,661,826. I

In the so called cracking processes, the heavy oils are submitted totemperatures 1n substantial excess of their normal boiling points bymaintaininghthe oils under relatively high pressures. e cracking of theoils is brought about solely by Virtue of heat reactions.

Temperatures used in modern commerclal plants are in excess of 450 C.

High temperatures mean correspondingly large fuel consumptions, the B.t. u. value of such fuel being equivalent to that of from 6 to 12 percent of the through put oil.

Local overheating tends toward the oxidation of the iron of the crackingapparatus, resulting in frequent bursting of the tubes.

Considerable difiiculty 1s experienced in cracking processes from theformation of carbon, in an amount equivalent to 5 to 15 percent of thethrough put oil, depending upon the character of the oil. This carbonrenders the iron brittle through the formation of iron carbides. Theconsequent result is that the ordinary cracking process is notcontinuous, {or the reason that the plant must be shut down to removethe adhering carbon.

In order to remove the suspended carbon in the oil, settling tanks ordigesters are in general necessary.

Besides the loss due to the formation ct carbon, ai'urther loss occursfrom the formation ofnon'condensible gases, representing from 6 to 12percent of the through put oil, according to the nature and character otthe oil.

Pressures used in modern commercial plants range from 100 to 1000lbsfand over.

Beause of the high pressures employed both in the tubes and in thesettling tanks there is an ever present danger of explosions.

Furthermore, high pressures require high powered pumps of special designfor circulating the oil through the system.

Because the desired cracking efiect is not produced in-a single stage ofthe operations, a great deal more heat must be' applied in reto crackingthe reflux oil than would be needed for all preheating purposes. Theprocess therefore requires large fractionators and enormous quantitiesof cooling water.

In order to get away from local overheata. ing in the tubes of thestill, it has been proposed to use external or internal metal baths.Among the metals suggested for such baths are those metals or alloyshaving melting points below 700 0., excluding, however,

metals which easily form carbides.

One of the better known so called catalytic processes employs tin, orits alloys, in reaction kettles coated on the inside with tin and provvided with baflies also coated with tin. In that process the reactionchamber is either heated up to a read heat (800 0.), at which crackingwould take place even without the presence of tin or its alloys, or elsethe process is carried out at lower temperatures employ- 8? ing acertain pressure and longer reaction time. In neither instance is theprocess, strictly speaking, a catalytic one." Even where the conversionof the oil hashegn carried out in the presence of tin and excess.quantities of hydrogen, the process cannot be considered a trulycatalytic one for the reason that tin is not a commercial hydrogenationcatalyst. 5

My process, however, is not a cracking to process in the sense in whichthe term is used, nor is it similar to the known so called catalyticprocesses. I do not maintain asuper atmospheric pressure in the reactionkettle. Furthermore, the temperature of the reaction i kettle is alwayskept below the boiling point of the oil to be treated and is, if Workingon heavy residue oils, not in excess of 400 C.

In my process the decomposition of the heavier hydrocarbon oils intooils of lower 1 boiling point, or, as in the production of blaugas, intogases, is accomplished by true catalytic action of high etiiciency onthe oil in a fog like state. I obtain higher yields than are realized inthe ordinary cracking processes or in known catalytical processes.

Where in the prior art, it has been suggested to carry out theconversion process with the oil in an atomized condition, it is evidentthat the conversion does not actually 1? take place with the oil in aliquid phase, since at the temperatures of red heat employed the oilmust necessarily be vaporized.

Moreover, by atomized has been meant a relatively finely dispersedcondition of the liquid oil effected by, (1) mechanically spraying theoil through a nozzle into a stationary body of gas, or (2)- by drawingthe oil into a moving stream of the gas, on the Bunsen principle, or (3)on the Koerting principle. In either case the globules of oil producedare so large and the surface of the globules so relatively small thatwhere the process is supposedly a catalytic one, efficient catalyticaction is impossible. In the second place the globules ofoil by virtueof their size and density are subject to the action of gravity and tendto coalesce, especially when in contact with the catalyzer. Theconsequence is that an oil layer is always formed on the surface of thecatalyzer, which layer distills off, leaving immediately a residue ofcoke.

My process contemplates not the atomization of the oil in the mannerbefore described and with the attendant disadvantages enumerated, butrather the production of a true fog of oil. The fog which I havereference to cannot be compared with the atomized or sprayed oil of theliterature, as it is entirely different in physical properties and inits behavior toward a decomposition catalyst. It is of such an extremestate of subdivision that it has all the properties of a true fog, beingsemi-opaque to the transmission of light, and comparatively insensibleto the attraction of gravity, remaining in a floating condition for anindefinite period of time.

It is therefore a very important object of this invention to provide afog producing device of special construction whereby the oil isdischarged under a definite pressure against a counterstream of gas andthus to efi'ect the conversion of the oil while the same is in a highlydispersed liquid phase. In this way a greater capacity of thereactionvessels is realized and a greater efficiency of catalytic actionis had than when the conversion takes place in the vapor phase. 1

Other and further important objects of my invention will be apparentfrom the disclosures in the following specification and appended claims.

ln carrying out my process, I employ a form of apparatus such asillustrated in the accompanying drawings in which:

Figure 1 is an elevational view of my apparatus, with parts in section.

Figure 2 is an enlarged sectional detail view of my oil fog producingdevice.

The oil to be converted is pumped by means of a pump 1 through apreheating coil 2, mounted in a chamber 3 above the firebox l of afurnace 5. Said furnace 5 may suitably be provided with a gas or oiltype burner 6 adapted to be easily controlled. A damper rea ers or gate7 between the firebox 1 and the heat" ing coil chamber 3 serves toregulate the tem perature in said chamber. The oil in the coil 2 ispreheated to a temperature of 200 to 350 C. under a pressure of 3 to 8atmos pheres, depending upon the characteristics of the oil to betreated. The oil then passes from the preheater coil 2 through aninsulated pipe 8 into an oil fog producing device 9 of my specialconstruction. Said oil fog producing device 9 extends through a sidewall of a reaction kettle .10 which is'supported in the brick work ofthe furnace 5 and is suspended, .as shown, in a compartment 11 thereof.A control damper 12 is 10 cated between the fire-box 4 and thecompartment 11 to enable the temperature of said compartment 11 to beeasily regulated.

The oil fog producing device 9 (Figure 2) comprises a passaged bodyportion 13 which extends through the wall of the kettlelO and is boltedthereto through an integral flange portion 14-. A Y-fitting 15, threadedinto said body portion, provides an oil passage 16, adapted to beconnected to the pipe 8 and a communicating passage 17 having anecdlevalve 18 for controlling the flow of oil through a nozzle 19 on theinner end of said passage 17. Said nozzle 19 together with an opposingnozzle 20 are positioned in a recess 21 provided for the purpose in ill)the lower side of said body portion 13. The

nozzle 20 is connected by means of a passage 22 to a pipe 23, whichserves to introduce some suitable gas or vapor into the fog producingdevice, as will later be explained. Said pipe 23 leads back to apreheating coil 24, positioned in the compartment 11 and serving topreheat the gas or vapor to substantially the temperature of thereaction kettle 10.

Said kettle 10 is preferably a relatively deep round bottomed kettlehaving a vertical partition 25 therein which extends from the top of thekettle to a point near the bottom thereof, as shown, and divides thekettle into two compartments 26 and 27 communicating with each other atthe bottom of the kettle. Compartment 26, which includes the fogproducing device 9 is preferablysmaller than compartment 27. The top ofthe kettle 10 has a flanged cover 28 in which are mounted a pressuregauge 29 and a thermometer well 30. The temperature within the reactionvessel is in general maintained between 250 and 400 0., depending uponthe nature of the oil which is being treated. If working on gas oil thetemperature employed is usually 280 to 350 6., but if working on lowerboiling hydrocarbons the temperature I may be less. On the other hand,if operating on high boiling residues and asphalts the temperature risesto 100 C.

Within the kettle 10 is placed a decomposition catalyst of my invention.Tin, tincially, I have found from experiment that if only 1% of antimonyis used, the highest decomposition factor is obtained. This isillustrated in the following table, which shows for differentpercentages of tin and anti-,

' 1nony, the corresponding decomposition factors and the correspondingyields of gasoline. Tests were made under the same operatingand'temperature conditions in an experimental plant, using the same Oileach time, which was a gas-spindle oil with a specific gravity of 0.88,a viscosity of 1.9 at 50 C. and a flash point of 1 40 C.

In these tests, the fractions having boiling points over 150 C. werefirst condensed in a bubble tower (fractionator) by temperature controland the resulting reflux pumped backonce more through the system. Thevapors leaving this bubble tower were lead into a gasoline tower wherethey were condensed. For the testmarked heat-pres sure test in thefollowing table, a pipe connection was made fromthe tube still direct.to the first bubble tower leaving out the reaction kettle, and byregulating a needle valve on the end of'this connecting line thepressure in'the furnace was maintained at atmospheres and a temperatureof 525 C. A high powered steam pump pumped the oil to the furnace andthis pump was later connected to the reflux. f v The decompositionfactor'referred to is based upon the number of c. c. of gasoline, havingan initial boiling point of 55 C. and an end boiling point of 150 0.,which is obtainable from 100 c. c. ofthe aforesaid spindle oil. Byassuming arbitrarily a unit decomposition factor for lead as a catalyst,I have beenable to express a simple relation between the decompositionfactors of the catalysts used.-

The table is as follows:

Description of process Decomposition factor 35 5 2 5 Per centHeat-pressure tests". we. (52575 atmospheres) 28 100% leadcataiyst...-.' 1 30 100% tin catalyst 1. 2 36 94% tin 6% antimony 2.1 6399% tin 1% antimony 2.5 75

It is thus apparent that a catalyst composed of tin containingapproximately 1% of antimony possessesremarkable value in the conversionof hydrocarbon oils.

The catalyst within the kettle 10 is maintained in a molten state at thetemperature above mentioned of between 250 and 400 C. The oil arrivingfrom the preheater 2 through the piping- 8 is discharged through thevalve regulated nozzle 19 against the gas issuing from the opposingnozzle 20. In first starting up my refining unit this gas may be eitherhydrogen, illuminating gas, water gas or some other .hydrogen containinggas. Hydrogen containing gas is used in the present case for the reasonthat my process contemplates subsequently hydrogenating the unsaturatedconversion prod ucts. However, the hydrogen plays no role other than asa carrier medium in the decomposition step of my process, since thecatalyst there used is not a hydrogenation catalyst. and the hydrogenmay therefore be subsequently introduced in the hydrogenation towers, ifdesired. After the unit has been operating, the fresh hydrogen supplymay be partially cut off and the residue or tail gases of the processmay be substituted in part. These gases would naturally contain acertain percentage ofhydrogen, since only a small fraction of thehydrogen originally introduced is consumed in the hydrogenation stage.It is evident that any deficiency in the quantity of hydrogen may bemade up from time to time by introducing fresh hydrogen into the system,or by constantly adding a small fraction of this gas. I do not use largeexcesses of hydrogen. Whatever the source of the gas, it is firstpreheated in the coil 24 located in the chamber 11 up to thetemperature. of the oil delivered from the preheating coil 2. Inpractice it has been found essential that the pressure of this should begreater by a certain proportional amount than the pressure of the oildelivered from the coil 2, this proportion depending upon the gravityand viscosity of the oil. This tends to a more balanced delivery of theoil and gas through the nozzles of the fog producer 9, and produces areal fog intermediate the opposing nozzles.

The concussion of the oil from the nozzle 19 and the gas from the nozzle20 results in the formation of a' grayish yellow fog. It is importantfor the formation and maintenance of this fog that the temperatures oftheoil and gas be the same, and that the impact of both constituentstake place in a space which shares the temperature of the reactionkettle. Accordingly, I have found that the atomization is mostsatisfactory if brought about within the reaction kettle itself. Byutilizing hydrogen, or gases containing hydrogen, I obtain the advantageof preventing a slow poisoning of the decomposition catalyst, whichadvantage is sometimes especially marked when operatingon heavy oils,asphalt and sulphurous oils. Any metal sulphides or oxides which mightbe formed are reduced immediately by the hydrogen, so that the tin andantimony reracticall indefipartment 27, until the head of molten metalsubstantially but not quite equals the pressure of thegas Within thecompartment 26.

Since no pressure of gas is maintained above the metal in compartment27, the tog and gas in compartment 26 is forced b its own pressure downthrough the body 0 metal in compartment 26 and under the lower edge ofthe baffle 25 and from there is forced to the surface in compartment 27by reason of the greater density of the metal. The oil in passingthrough the catalyst remains in its condition as a fog, until by virtueof the decomposing action of the catalyst it is converted intohydrocarbons of such lower boiling points that, underthe conditions oftemperature and pressure obtaining, such oils are vaporized. It isevident, therefore, that the conversion into hydrocarbons of lowerboiling point takes place strictly in the liq-' uid phase. This is ofenormous'advantage since the volume of the catalyst and reaction vesselneed not be nearly so great as if the decomposition occurred in gaseousstate. The internal pressure of the molten metals on the globules ofoil, and also the protecting action of the gas surroundingthe oilparticles, act to prevent in part the vaporiza tion of the hydrocarbonconversion products while passing through the catalyst.

I have found that a fog of oil such as formed in my process will passthrough the molten catalyst as stated but that oil in bulk, or in finelydivided streams or in an atomized or finely dispersed condition, whenforced through the same molten catalyst, will rise to the surfacepractically undecomposed and there undergo ordinary distillation,leaving the usual coke and carbon residues on the surface'of thecatalyst and plugging up the whole systemin a few hours. The formationof the fog, therefore, is a most import-- ant step in my process.

The vapors of the converted hydrocarbon oils accumulating in theopenspace in compartmeut 27 are led off through a conduit 31 into the base32 of a tower 33. The base 32' is filled with an absorbing medium 34,such as iron and manganese oxides, or any other suitable desulphurizer,for the purpose of removing any sulphurous compounds that may beprcsent.The oxides may be removed and regenerated from time to time as required.It

will be noticed that the base 32 is insulated as at 35. This is for thepurpose of prevent ng undue cooling with consequent condensation I ofthe vapors at this point. a

The oil vapors and hydrogen containing gases.

gases next pass through'a condensate tra 36 into the main portion ofthetower, whic is filled with iron or steel turnings. V The upper partnf tower 33 is provided with a straight tube condenser 37, from whichthe conden sates formed therein trickle down onto the trap 36. Fromthere the condensates are discharged through a pipe 38 into rundowntanks 39. From the top of the tower33, the vapors and gases are ledthrough a pipe 40 into the baseof a tower 41. Said tower 41 is dividedinto'three horizontal compartments 42, 43 and 44, containing iron,copper and nickel turnings respectively. These different metal turningsall act as hydrogenation catalysts and are arranged in accordance withtheir respective temperature require ments for'efficient catalyticaction. The use 'of various hydrogenatiomcatalysts is old in the art butI claim as new'the arrangement of catalysts according totheir mosteflicient reacting temperatures. 'For instance, iron shows greatestactivity as a hydrogenation catalyst at higher temperatures than eithercopper or nickel, and copper at higher temperatures than nickel. Theyare accordingly conducted from the top of the condenser 45 by way of apipe 48 into a final condenser 49. From said condenser 49, thecondensates pass through pipe 50 into run-down tanks 51. The uncondensedgases from the final condenser 49 are conducted by a pipe 52 to acompressor 53. Said compressor 53 subjects these gases to a pressure ofapproximately 15 atmospheres and delivers the compressed gases through apipe 54 into a pressure tank 55, which is cooled inside by means ofstraight water tubes 60. At the side of this tank is a pressure reliefvalve 59, which is so arranged that it blows off to maintain the gas inthe return pipe 58 at a definite pressure, depending upon the oilto betreated. Another relief valve 61 is used for relieving the amount ofgasnot needed for recirculation to gas burners under the-still. Thecooling of the compressed vapors in the pressure tank results in thecondensation of a portion of the The condensate so formed is led througha pipe 56 into pressure run-d'own tanks 57 The uncondensed hydrogenoustail gases are expanded from the side of the tank'55 and led through thereturn piping 58 back to the preheater 24 and thence to the fogproducing device 9.

I am aware that numerous changes may be low ' in the liquid phase,

made without departing from the principles of this invention, and Itherefore do not purpose limiting the patent granted hereon otherwisethan necessitated by the prior art.

I claim as my invention:

1. A process of converting hydrocarbon oils into loweriboiling productswhich includes the'ste'p of directing a. hydrocarbon oil against acounter current stream of a gas-under sufli'cient pressure to form atrue fog of oil andthen passing said fog through a molten decompositioncatalyst consisting of an alloy' of tin and antimony containingless than10% antimony, whereby decomposition of the oil takes place in the liquidphase, the resulting lower boiling products being released from saidcatalyst in vapor form.

2. A process of converting hydrocarbon oils into lower boiling productswhich includes the step of directing a hydrocarbon oil against a countercurrent stream of a gas under suflicient pressure to form a true fog ofoil and then passing said'fog through a molten decomposition catalystconsisting of an alloy of tin and antimony containing less than 10%antimony, said catalyst being maintained at and 400 0;,

a temperature of between 250 y decomposition of the oil takes placewhere the resulting lower boiling oils being released from said catalystin vapor form. 4

3. A process of converting hydrocarbon oils into lower boiling oils,which includes the I step of forming a true fog of oil suspended in agas, said oil and gas having been preheated to substantially thetemperature employed in the subsequent decomposition step and thenpassing said fog. through a molten decomposition catalyst, consisting ofan alloy of tin and antimony containing less than10% antimony, saidcatalyst being maintained at a temperature of between 250 and 400 (3.,whereby decomposition of the oil takes place in the liquid phase, theresulting lower boiling oils being released from said catalyst invaporform. g

4. A process of converting hydrocarbon oils intolower.boilinghydrocarbons, which includes the step of forming a true fogof oil suspended in .a gaseous medium, said oil and gaseous mediumhaving been preheated'to substantially the temperature employed inpassing said fog at substantially atmospheric pressure through a moltendecomposition catalyst consisting of an alloy of tin and antimonycontaining less than 10% antimony, said catalyst being maintained at atempera ture of between 250 and 400 0., whereby decomposition of thehigher boiling oil takes place in the liquid phase, the resulting lowerthe subsequent decomposition step and then boiling hydrocarbons beingreleased from said catalyst in vapor form.

5. The process of refining oils, which includes subjecting the-oil inthe formof a true fog at a temperature above atmospheric to the actionof a decomposition catalyst comprised of tin and antimony, the latterbeing present in an amount equal to less than 10% of the tin. 6. Theprocess of refining oils, which includes subjecting the oil at atemperature about atmospheric while in a highly. dispersed fog-likeliquid phase to the action of a decomposition catalyst comprised of tinantimony alloy containing less than 10% antimony.

7. The process'of refining oils, which includes subjecting the oil whilein a. highly dispersed fog-like liquid phase to the action of adecomposition catalyst comprised of tin anti- 'mony alloy containingless than-10% of antimony and maintained in a molten condition at atemperature of between 250 and 400 C.

8. The process of refining oils, which includes subjecting the oil whilein ahighly dispersed fog-like liquid phase at a temperature aboveatmospheric to the action of a decom= position catalyst comprised of tinantimony alloy cont-ainingless than 10% of antimony and maintained inamolten condition at a temperature below the normal boiling point of theoil. k

9; The process of refining oils, which includes subjecting the oil whilein the form of a true fog and at substantially atmospheric pressure tothe action of a decomposition tained in a molten condition at atemperature T of between 250 and 400 C.

In testimony whereof I have hereunto sub- PH. D.

name.

scribed my ERIC TH. HESSLE,

